1. Field of the Invention
This invention relates to the production of comestible products, particularly to the production of thermostable edible cremes. The invention also relates to the production of ready-to-eat cooked dough products, i.e., baked or fried dough products, in which a thermostable creme is combined with the dough prior to cooking.
2. Prior Art
Most creme-filled dough products, e.g., filled pastries, cookies and the like, are produced by first cooking a dough preform and then filling the cooked preform with the creme. The post-cook filling procedure is generally inconvenient and expensive, particularly in the commercial scale production of ready-to-eat creme-filled products. Pre-cook application of the creme to the dough product has not been widely employed because most of the edible cremes known in the prior art have exhibited poor thermal stability.
Edible cremes known in the prior art generally have high moisture levels and high water activities (typically, A.sub.w values of about 0.8 to 0.9). The water activity of a food is defined as the partial vapor pressure of water in the food divided by the saturation vapor pressure of pure water at the temperature of the food. It can be measured by placing a sample in a container, which is then sealed, and determining the relative humidity above the sample after equilibrium is reached. Water activity can be considered to be a measure of the tendency of a material to allow moisture to migrate out of the material to its surrounding environment.
The water activities of prior art cremes have been highly dependent on their water content. In order to achieve desirably creamy textures, it has been necessary to incorporate relatively large amounts of water into these creams, which has resulted in high water activities. The high water activities associated with these cremes are problematical, especially when the creme is used in a product in which it is in contact with a material of considerably lower water content, such as a baked pastry dough. Due to the disparity in moisture contents of the two materials and the relatively high water activity of the creme, moisture tends to migrate from the creme into the pastry dough, making the pastry soggy.
Cremes having high water activities also provide a medium which is conducive to microbial growth. Thus, ready-to-eat products containing cremes of the prior art tend to have limited shelf lives due to microbial growth.
It would be highly desirable to produce a thermostable edible creme having a low water activity, i.e., a water activity below about 0.7. Moreover, it would be desirable to produce such a creme in which the water activity is relatively independent of water content so that the texture can be controlled independently of water activity.